Laboratory Medicine Updates - January 23, 2003

University of Virginia Health System

Medical Laboratories

“Quality You Expect, Service You Deserve”

LABORATORY MEDICINE UPDATE

January 23, 2003

Successful Inspection of Medical Laboratories

The UVa Medical Laboratories were inspected by a twenty-member inspection team from the University of Arkansas Medical Center on behalf of our accrediting agency the College of American Pathologists on January 13 and 14, 2003. The Medical Laboratories have been recertified for a full two year term, the maximum possible period.

Anti-Cardiolipin Reference Interval Change

Due to reagent availability, the Immunology Division of the Medical Laboratories has changed vendors for anti-cardiolipin test reagents. This has resulted in the following new reference intervals:

Anti-cardiolipin IgG: Negative < 15.0 GPL

Equivocal 15.0 – 20.0 GPL

Positive > 20.0 GPL

Anti-cardiolipin IgM: Negative < 12.5 MPL

Equivocal 12.5 – 20.0 MPL

Positive > 20.0 MPL

Prothrombin Time and Fibrinogen Reference Interval Changes

The coagulation laboratory has adjusted the reference intervals effective January 16, 2003 for Prothrombin Time (PT) testing and fibrinogen levels due to a change in reagent lot. The new values are:

Prothrombin Time: 12.2 – 15.3 s

ISI = 1.30

Mean = 13.7 s

Fibrinogen: 155 – 398 mg/dL

New Test Version for HIV Viral Load Testing

The Molecular Diagnostics Laboratory has changed the HIV Viral Load assay from the Roche Monitor (version 1.0) test to the Roche Monitor (version 1.5) test. This new version of the test has enhanced sensitivity for additional sub-types of HIV. The test results in the patients’ records indicate which version of the test was used, as recommended in the CDC guidelines for reporting of HIV Viral Load results.

In the evaluation, an average 0.1 log (base 10) increase with the new version compared to the old was seen (n=20, 10 ultrasensitive and 10 “regular” HIV specimens, range -0.2 to 0.4). This is comparable to what has been reported in the literature.

According to Roche, this assay has been shown to detect all of the following subtypes (specific isolates tested) of HIV:

A (UG273, DJ258, DJ263)

B (US1, US2, US3, US4, CM237, BK132, BZ167)

C (ZAM18, UG268, ETH2220, SE364, SM145)

D (SE365, UG270, UG274)

E (CM235, CM238, CM240, CM243, POC30506, ID12, ID17,

NP1465)

F (BZ126, BZ162, BZ163)

G (HH8793)

New Instrumentation for Urinalysis in the UVa Core Laboratory

In December 2002, the Clinical Core Laboratory implemented two new instruments for urinalysis. One analyzer is used to perform the biochemical analysis of the urine (automated dip-stick) while the other analyzer performs the microscopic examination. The reporting of the biochemical analysis has not changed; however, reporting of the microscopic examination has changed:

The new report from the microscopic exam includes enumeration of Red Blood Cells, White Blood Cells, Casts, Epithelial Cells, Bacteria, and additional findings.

The report for Casts is for Hyaline Casts only. Other types of Casts will be reported under “additional findings.”

The report for Epithelial Cells is specific for Squamous Epithelial Cells. Other types of epithelial cells will be reported under “additional findings.”

This new instrumentation has decreased the turn-around-time for analysis of normal urines. Additionally, the analyzer performing the microscopic examination uses new laser technology for improved detection of abnormal findings.

Quantitative Immunoglobulin D (IgD) Testing now being sent to Quest

Due to a lack of reagent availability, IgD testing is now being sent to our referral lab, Quest Diagnostics. The specimen requirement is 1 mL of serum (gold top tube). The assay is performed two days a week using radial immunodiffusion technology. There is no change in the reference intervals.

New Test Code for Capillary Lead Samples

Due to a requirement by the Commonwealth of Virginia for the reporting of all pediatric lead testing, including sample type, a second test code for lead testing has been implemented.

For samples collected by standard venipuncture techniques, please continue to use QLEAD or enter LEAD in the “other tests” portion of the outpatient laboratory test request form.

For samples collected by fingerstick (capillary samples), please use QCLEAD or enter CAPILLARY LEAD in the “other tests” portion of the outpatient laboratory test request form.

Sample Requirements for Diagnosis of Neuroborriliosis

In order to provide the appropriate testing for the diagnosis of neuroborriliosis, it is recommended that both serum and CSF be assayed for the presence of antibody against B. burgdorferi and the ratio calculated. In the interest of timely result reporting, both a CSF and serum sample, collected within 24 hours of each other, must be submitted for testing. Only those patients in whom CSF antibody is detected will have the serum specimen analyzed.

Request for Clinical History/Information for Genetic Testing

The Molecular Diagnostics Laboratory currently offers genetic testing for Factor V/Factor II, hemochromatosis (HFE) and fragile X syndrome and additional tests are being developed. Due to the complexity of testing and interpretation, in order to provide meaningful interpretive reports and to determine the appropriateness of genetic testing, adequate and appropriate clinical information is necessary on all requests for genetic testing. This can be provided as a brief clinical note on the request form, analogous to requests for radiologic or clinical consults. A laboratory order form for Molecular Diagnostics and Special Coagulation tests is available for this purpose. As this is a compliance issue for the hospital and the laboratory, failure to supply this information at the time the sample is submitted will delay reporting of results.